Question

a wheel makes 40 revolutions per minute at this rate how many minutes does it take the wheel to make 280 revolutions

Answer 1

It would take 7 minutes. 

Because it makes 40 revolutions per minute, and it needs to make 280 revolutions, you can find it by 280/40, which equals 7.

Answer 2

40 revolution in 1 minute
280 revolutions in x minutres

X= 280•1/40= 280/40= 28/4=7 minutes